fix(ci): Fix Docker fuzzing in GitHub Actions

- Remove problematic cache_from directive (non-existent registry image)
- Remove Docker layer caching (causing issues in CI)
- Make Cargo.lock optional in Dockerfile (COPY Cargo.lock* ./)
- Simplify docker compose build command
- Remove BUILDKIT_INLINE_CACHE build arg

This fixes:
- Cache import error from non-existent crabgraph-fuzz:latest
- Cargo.lock not found error in Docker context
- Cache key computation errors

Author: AriajSarkar

.github/workflows/fuzz.yml

@@ -15,18 +15,9 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
-      - name: Cache Docker layers
-        uses: actions/cache@v4
-        with:
-          path: /tmp/.buildx-cache
-          key: ${{ runner.os }}-buildx-fuzz-${{ hashFiles('Dockerfile.fuzz', 'Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-buildx-fuzz-
-      
       - name: Build fuzz Docker image
         run: |
-          docker compose -f docker-compose.fuzz.yml build \
-            --build-arg BUILDKIT_INLINE_CACHE=1
+          docker compose -f docker-compose.fuzz.yml build
       
       - name: Run fuzzing (60 seconds per target)
         run: |

Dockerfile.fuzz

@@ -31,7 +31,8 @@ RUN rustup default nightly
 WORKDIR /workspace
 
 # Copy Cargo files first for better layer caching
-COPY Cargo.toml Cargo.lock ./
+COPY Cargo.toml ./
+COPY Cargo.lock* ./
 COPY fuzz/Cargo.toml ./fuzz/
 
 # Create dummy src to build dependencies (caching layer)

docker-compose.fuzz.yml

@@ -3,8 +3,6 @@ services:
     build:
       context: .
       dockerfile: Dockerfile.fuzz
-      cache_from:
-        - crabgraph-fuzz:latest
     image: crabgraph-fuzz:latest
     container_name: crabgraph-fuzz
     volumes: